Grand Duke Guillaume is celebrating his 45th birthday on Wednesday, marking more than a year since he officially ascended to the throne as Luxembourg's head of state.
Born on 11 November 1981, Guillaume is the eldest child of Grand Duke Henri and Grand Duchess Maria Teresa. He was officially proclaimed Hereditary Grand Duke on 18 December 2000, positioning him from an early age to eventually lead the Luxembourgish monarchy. He formally assumed the role of Grand Duke on 3 October 2025.
The Grand Duke has been married to Countess Stéphanie de Lannoy since October 2012. The couple has two sons: Prince Charles Jean Philippe Joseph Marie Guillaume, born at the Grand Duchess Charlotte Maternity Hospital in Luxembourg City on 10 May 2020, and Prince François Henri Louis Marie Guillaume, born on 27 March 2023.
